Optical phased array light steering

Abstract

An apparatus includes: an optical phased array (e.g., on a photonic integrated circuit), a focusing element, which can be at a fixed position relative to the optical phased array and configured to receive an optical beam from the optical phased array, and a steering element, which can be at a fixed position relative to the focusing element and configured to transmit the optical beam received from the focusing element. In some implementations, at least one of the focusing element or the steering element is externally coupled to the photonic integrated circuit.

What is claimed is: 
     
       1. An apparatus comprising:
 a photonic integrated circuit comprising an optical phased array comprising a plurality of antenna elements that are coupled to respective optical waveguides formed in the photonic integrated circuit, 
 a focusing element at a fixed position relative to the optical phased array and configured to couple an optical beam to or from two or more of the plurality of antenna elements of the optical phased array, and 
 a steering element at a fixed position relative to the focusing element and configured to steer the optical beam to or from the focusing element over a plurality of different angles within a steering range that is determined at least in part by at least one characteristic of the optical beam; 
 wherein at least one of the focusing element or the steering element is externally coupled to the photonic integrated circuit. 
 
     
     
       2. The apparatus of  claim 1 , wherein the steering element comprises a dispersive element. 
     
     
       3. The apparatus of  claim 2 , wherein the dispersive element comprises a diffractive element. 
     
     
       4. The apparatus of  claim 2 , wherein the dispersive element comprises a refractive element. 
     
     
       5. The apparatus of  claim 4 , wherein the refractive element comprises a prism. 
     
     
       6. The apparatus of  claim 2 , wherein the dispersive element comprises at least two prisms. 
     
     
       7. The apparatus of  claim 2 , wherein the dispersive element comprises at least one diffraction grating and at least one prism. 
     
     
       8. The apparatus of  claim 1 , wherein the focusing element comprises a lens. 
     
     
       9. The apparatus of  claim 1 , wherein the focusing element comprises a reflective surface, and the reflective surface is configured to provide both reflection and focusing. 
     
     
       10. The apparatus of  claim 1 , wherein the photonic integrated circuit, the focusing element, and the steering element are included in at least a portion of a LiDAR system. 
     
     
       11. The apparatus of  claim 1 , wherein the photonic integrated circuit, the focusing element, and the steering element are included in at least a portion of a free space optical link of a communication system. 
     
     
       12. The apparatus of  claim 1 , further comprising an optical source configured to provide an optical wave to the antenna elements of the optical phased array. 
     
     
       13. The apparatus of  claim 12 , wherein relative phase shifts among the antenna elements provide steering of the optical beam emitted from the optical phased array in a first plane. 
     
     
       14. The apparatus of  claim 13 , wherein the steering element comprises a dispersive element, the optical source comprises a tunable optical source configured to tune a wavelength of the optical wave provided to the antenna elements of the optical phased array, and the tuned wavelength provides steering of the optical beam emitted from the dispersive element in a second plane perpendicular to the first plane. 
     
     
       15. The apparatus of  claim 1 , wherein relative phase shifts among the antenna elements of the optical phased array provide steering of the optical beam emitted from the optical phased array in a first plane, and the steering element provides steering of the optical beam in a second plane perpendicular to the first plane. 
     
     
       16. The apparatus of  claim 15 , wherein the relative phase shifts among the antenna elements are applied through respective phase shifters coupled to the respective antenna elements. 
     
     
       17. An apparatus comprising:
 an optical phased array comprising a plurality of antenna elements that are coupled to respective optical waveguides, 
 a reflective surface at a fixed position relative to the optical phased array and configured to redirect an optical beam to or from two or more of the plurality of antenna elements of the optical phased array, and 
 a steering element at a fixed position relative to the reflective surface and configured to steer the optical beam to or from the reflective surface over a plurality of different angles within a steering range that is determined at least in part by at least one characteristic of the optical beam. 
 
     
     
       18. The apparatus of  claim 17 , wherein the reflective surface is shaped to substantially collimate the optical beam in at least a first plane when the optical beam is redirected from the optical phased array. 
     
     
       19. The apparatus of  claim 18 , further comprising an optical source configured to provide an optical wave to the antenna elements of the optical phased array. 
     
     
       20. The apparatus of  claim 19 , wherein relative phase shifts among the antenna elements provide steering of the optical beam emitted from the optical phased array in a second plane perpendicular to the first plane. 
     
     
       21. The apparatus of  claim 20 , wherein the steering element comprises a diffractive element, the optical source comprises a tunable optical source configured to tune a wavelength of the optical wave provided to the antenna elements of the optical phased array, and the tuned wavelength provides steering of the optical beam emitted from the diffractive element in the first plane. 
     
     
       22. The apparatus of  claim 20 , wherein the steering element comprises a diffractive element that is configured to be tuned electronically to steer the beam in the first plane. 
     
     
       23. The apparatus of  claim 17 , wherein the optical phased array, the reflective surface, and the steering element are included in at least a portion of a LiDAR system. 
     
     
       24. The apparatus of  claim 17 , wherein the optical phased array, the reflective surface, and the steering element are included in at least a portion of a free space optical link of a communication system. 
     
     
       25. The apparatus of  claim 17 , wherein relative phase shifts among the antenna elements of the optical phased array provide steering of the optical beam emitted from the optical phased array in a first plane, and the steering element provides steering of the optical beam in a second plane perpendicular to the first plane. 
     
     
       26. An apparatus comprising:
 an optical phased array comprising a plurality of antenna elements that are coupled to respective optical waveguides, 
 a lens at a fixed position relative to the optical phased array and configured to couple an optical beam to or from two or more of the plurality of antenna elements of the optical phased array, and 
 a steering element at a fixed position relative to the lens and configured to steer the optical beam to or from the lens over a plurality of different angles within a steering range that is determined at least in part by at least one characteristic of the optical beam. 
 
     
     
       27. The apparatus of  claim 26 , wherein the lens is shaped to substantially collimate the optical beam in at least a first plane when the optical beam is coupled from the optical phased array. 
     
     
       28. The apparatus of  claim 27 , further comprising an optical source configured to provide an optical wave to the antenna elements of the optical phased array. 
     
     
       29. The apparatus of  claim 28 , wherein relative phase shifts among the antenna elements provide steering of the optical beam emitted from the optical phased array in a second plane perpendicular to the first plane. 
     
     
       30. The apparatus of  claim 29 , wherein the steering element comprises a diffractive element, the optical source comprises a tunable optical source configured to tune a wavelength of the optical wave provided to the antenna elements of the optical phased array, and the tuned wavelength provides steering of the optical beam emitted from the diffractive element in the first plane. 
     
     
       31. The apparatus of  claim 29 , wherein the steering element comprises a diffractive element that is configured to be tuned electronically to steer the beam in the first plane. 
     
     
       32. The apparatus of  claim 26 , wherein the optical phased array, the lens, and the steering element are included in at least a portion of a LiDAR system. 
     
     
       33. The apparatus of  claim 26 , wherein the optical phased array, the lens, and the steering element are included in at least a portion of a free space optical link of a communication system. 
     
     
       34. The apparatus of  claim 26 , wherein relative phase shifts among the antenna elements of the optical phased array provide steering of the optical beam emitted from the optical phased array in a first plane, and the steering element provides steering of the optical beam in a second plane perpendicular to the first plane. 
     
     
       35. An apparatus comprising:
 a plurality of optical phased arrays, and 
 a focusing element at a fixed position relative to the optical phased arrays and configured to couple optical beams to or from respective optical phased arrays of the plurality of optical phased arrays, 
 wherein the focusing element is positioned and configured to substantially collimate at least a first optical beam of the optical beams in at least a first plane when the first optical beam is coupled from a respective first optical phased array of the plurality of optical phased arrays, and 
 wherein the plurality of optical phased arrays are arranged on respective pedestals, where each optical phased array comprises a linear array of emitter elements arranged along a first axis, and each linear array of emitter elements is offset with respect to the other linear arrays along the first axis and offset with respect to the other linear arrays along a second axis perpendicular to the first axis. 
 
     
     
       36. The apparatus of  claim 35 , wherein the optical phased arrays and the focusing element are included in at least a portion of a LiDAR system. 
     
     
       37. The apparatus of  claim 35 , wherein the optical phased arrays and the focusing element are included in at least a portion of a free space optical link of a communication system. 
     
     
       38. The apparatus of  claim 35 , wherein the first optical phased array comprises a plurality of antenna elements that are coupled to respective optical waveguides and is configured to provide the first optical beam formed from interference among optical waves emitted from two or more of the plurality of antenna elements of the first optical phased array. 
     
     
       39. The apparatus of  claim 38 , wherein a second optical phased array of the plurality of optical phased arrays comprises a plurality of antenna elements that are coupled to respective optical waveguides and is configured to receive a second optical beam of the optical beams into two or more of the plurality of antenna elements of the second optical phased array. 
     
     
       40. The apparatus of  claim 38 , wherein a second optical phased array of the plurality of optical phased arrays comprises a plurality of antenna elements that are coupled to respective optical waveguides and is configured to provide a second optical beam of the optical beams formed from interference among optical waves emitted from two or more of the plurality of antenna elements of the second optical phased array. 
     
     
       41. An apparatus comprising:
 an optical phased array comprising a plurality of antenna elements that are coupled to respective optical waveguides, and 
 a focusing steering element at a fixed position relative to the optical phased array and configured to receive an optical beam formed from interference among optical waves emitted from two or more of the plurality of antenna elements of the optical phased array, 
 wherein the focusing steering element is configured to: substantially collimate the optical beam in at least a first plane, and steer the optical beam in the first plane over a plurality of different angles within a steering range that is determined at least in part by at least one characteristic of the optical beam. 
 
     
     
       42. The apparatus of  claim 41 , wherein the focusing steering element comprises a focusing diffractive element. 
     
     
       43. The apparatus of  claim 41 , wherein the optical phased array and the focusing steering element are included in at least a portion of a LiDAR system. 
     
     
       44. The apparatus of  claim 41 , wherein the optical phased array and the focusing steering element are included in at least a portion of a free space optical link of a communication system. 
     
     
       45. An apparatus comprising:
 an optical phased array comprising a plurality of antenna elements that are coupled to respective optical waveguides, 
 a reflective focusing element at a fixed position relative to the optical phased array and configured to couple an optical beam to or from two or more of the plurality of antenna elements of the optical phased array, and 
 a diffractive element at a fixed position relative to the reflective focusing element and configured to transmit the optical beam to or from the reflective focusing element. 
 
     
     
       46. The apparatus of  claim 45 , wherein the reflective focusing element comprises a reflective surface, and the reflective surface is configured to provide both reflection and focusing. 
     
     
       47. The apparatus of  claim 45 , wherein the diffractive element comprises a curved diffractive element that transmits the optical beam through the curved diffractive element. 
     
     
       48. The apparatus of  claim 45 , wherein the optical phased array and the reflective focusing element are included in at least a portion of a LiDAR system. 
     
     
       49. The apparatus of  claim 45 , wherein the optical phased array and the reflective focusing element are included in at least a portion of a free space optical link of a communication system.